The Community Programs for Clinical Research on AIDS (CPCRA) is a community-based clinical trials group which proposes to include 19 units in the United States and clinical sites in Australia, Canada, and the United Kingdom. This is a proposal for the Statistical and Data Management Center (SDMC) for this trials group. The SDMC bears primary responsibility for the statistical components of the science agenda outlined in the accompanying core proposal. The SDMC also has primary responsibility for the development of data collection, management, and reporting procedures that ensure that the studies are properly implemented and monitored. Objectives fall into four broad and interrelated areas: l) to provide statistical leadership to the group by collaborating on the development of an integrated scientific agenda, by using innovative approaches in the design of studies, by carrying out interim and final analyses, and by conducting seminars on research methods; 2) to continue to enhance systems for collecting, processing and reporting data in a timely and efficient way so that study objectives are met; 3) to collaborate with national trial coordinating centers in Australia, Canada, and the United Kingdom which will assist with randomization procedures, data management, and data analysis, and to collaborate with other clinical trial groups on specific studies; and 4) to work closely with all of the organizational groups and committees in the CPCRA to carry out the scientific agenda, and to maintain a SDMC organizational structure and staff that aligns with the larger CPCRA organization and provides a stimulating work atmosphere and peer support.